MeDALL improves the methodology to evaluate asthma and allergies in Europe

Monday, March 31th, 2014

Numerous cohorts focusing on asthma and allergy have been initiated in the world over the past 30 years, most of them focusing on the evaluation of incidence, course and risk factors of asthma and allergies. In Europe, the costs of persistent asthma were estimated at EUR 19.3 billion and most costs were due to young patients aged 15–30 years. Many EU-funded research initiatives have attempted to evaluate determinants of asthma and allergies by comparing pooled data from existing European birth cohorts to potentially identify underlying mechanisms explaining associations between diseases and environmental exposures resulting from heterogenous results among these cohorts.

To improve comparability among birth cohorts, MEDALL researchers made the effort to harmonize questions following a rigorous four stepwise process to develop a common core questionnaire to be used by all birth cohorts during the follow-up. This questionnaire included both core questions and supplementary questions which remained optional for the participating cohorts. In total we developed three MEDALL core questionnaires: 2 for parents of children aged 4–9 and 14–18, respectively and 1 for adolescents aged 14–18 to be used by ) 11 European birth cohorts (Denmark, France, Germany, Greece, Italy, Netherlands, Norway, Spain, Sweden and the United Kingdom) over 13,000 children during the follow-up assessments.

Dr. Mariona Pinart, researcher of CREAL, an ISGlobal research centre, remarks that “these news questionnaires are to our knowledge the first attempt to develop a multilingual common core questionnaire for birth cohorts examining asthma and allergy. In addition, they will produce more comparable data across different cohorts and countries in Europe and will offer the possibility to verify results of former cohort analyses. Thus, MeDALL can become the starting point to stringently plan, conduct and support future common asthma and allergy research initiatives in Europe.”

Former questionnaires used by many cohorts to assess symptoms of asthma and rhinitis included several questions based on those developed and validated in the worldwide International Study of Asthma and Allergies in Childhood (ISAAC). Although the order and/or wording of the ISAAC questions were usually slightly modified, questions on asthma and allergic rhinitis were homogeneously assessed across European birth cohorts. On the other hand, the assessment of other allergic phenotypes (e.g. eczema, sensitization to aero- and food allergens), pulmonary development and possible determinants of allergic diseases, including dietary habits and environmental exposures, were rather heterogeneous.

In this regard, MeDALL project attempts to increase the amount of harmonized questions beyond those included in the ISAAC questionnaire or those which might have been included in the ISAAC questionnaire but were not frequently used by the cohorts in the last years.